by David Whitman, Paul Glastris, and Brendan I. Koerner

About the authors: David Whitman, Paul Glastris, and Brendan I. Koerner write for U.S. News & World Report.

Teen pregnancy, President Bill Clinton says, is the nation’s “most serious social problem,” and he has vowed to do something about it. The issue is a frequent “talking point” in his speeches, and, in an elegant White House ceremony in 1997 designed to underscore the administration’s commitment, the first lady honored a dozen organizations for their work in tackling the problem.

For Clinton, as for politicians of every partisan stripe, lamenting the scourge of “babies having babies” is a no-lose proposition. Who could object? In preaching the virtues of abstinence during adolescence, however, the president and the first lady are...